Safety switches, such as disclosed in DE 44 08 024 A1, serve to make the current supply feeding electrical machinery dependent upon whether certain protection devices, which are integral with the machine, are positioned in the correct setting. With some embodiments, the safety switch does not connect the control current circuit supplying a current supply to the machine because the protection devices have greater tolerances than allowed by the safety switch.
EP-A1-0 707 329 discloses a safety switch with a plate cam mounted rotatably on an axis on which are arranged interlocking means. The interlocking means lock or secure the plate cam when the key is not introduced and are thrust out of their blocking position when the key is introduced. The plate cam is released with further introduction of the key, with the interlocking means being rotated together with the plate cam.